(1968). Biological conservation. Amsterdam : Elsevier Science Pub..
Lua i Stíl Chicago (17ú heag.)Biological Conservation. Amsterdam : Elsevier Science Pub., 1968.
Lua MLA (9ú heag.)Biological Conservation. Amsterdam : Elsevier Science Pub., 1968.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.